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Contingencies and commitments - Narrative (Details) $ in Millions |  |  |  |  |  | 1 Months Ended | 2 Months Ended | 3 Months Ended | 9 Months Ended | 15 Months Ended | 61 Months Ended
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Oct. 02, 2025 USD ($) | Jul. 28, 2025 Plaintiff | Oct. 31, 2023 USD ($) Cases | Jul. 29, 2022 a Structure People | Aug. 16, 2020 a Wildfire | Oct. 31, 2025 USD ($) Plaintiff | Dec. 31, 2024 USD ($) Plaintiff | Sep. 30, 2024 USD ($) | Apr. 30, 2024 USD ($) | Jan. 31, 2024 USD ($) | Jun. 30, 2023 USD ($) Plaintiff | Nov. 30, 2021 USD ($) | Sep. 30, 2020 a Structure | Oct. 31, 2024 USD ($) shares | Sep. 30, 2025 USD ($) | Sep. 30, 2025 USD ($) Cases Damage | Sep. 30, 2024 USD ($) | Jun. 30, 2025 USD ($) | Sep. 30, 2025 USD ($)
Pilot [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Remaining noncontrolling interests acquired |  |  |  |  |  |  |  |  |  | $ 2,600 |  |  |  |  |  |  |  |  |
OxyChem [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire business | $ 9,700 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
BHE [Member] | Common Class B [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares exchanged | shares |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,291,631 |  |  |  |  |
Value of shares exchanged |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,045 |  |  |  |  |
Berkshire Hathaway Energy [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of outstanding common stock repurchased |  |  |  |  |  |  |  | 5.85% |  |  |  |  |  |  |  |  | 5.85% |  |
Consideration for repurchase of common stock held by noncontrolling shareholders |  |  |  |  |  |  |  | $ 2,900 |  |  |  |  |  |  |  |  |  |  |
Berkshire Hathaway Energy [Member] | HomeServices of America [Member] | Antitrust Cases [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 9,000 |  |  |
Number of cases | Cases |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |
Berkshire Hathaway Energy [Member] | HomeServices of America [Member] | Antitrust Burnett Case [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, awarded value |  |  | $ 1,800 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Legal settlements amount paid |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 67 |
Litigation settlement, scheduled payments term |  |  |  |  |  |  |  |  | 4 years |  |  |  |  |  |  |  |  |  |
Settlement payments to be paid |  |  |  |  |  |  |  |  | $ 250 |  |  |  |  |  |  |  |  |  |
Number of cases | Cases |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
NICO [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency accrual |  |  |  |  |  |  |  | 535 |  |  |  |  |  |  |  |  |  |  |
Net loss contingency accrual |  |  |  |  |  |  |  | 490 |  |  |  |  |  |  |  |  |  |  |
Loss contingency recoverable from a third party, received |  |  |  |  |  |  |  | $ 45 |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated pre-tax probable loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,850 | $ 2,850 |  |  | $ 2,850
Legal settlements amount paid |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,400
Unpaid estimated liability |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,450 | 1,450 |  |  | $ 1,450
Loss contingency accrual |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 100 | 100 | $ 251 |  |
Insurance recoveries |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 530 |  |  |
PacifiCorp [Member] | 2020 Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 55,000 |  |  |
PacifiCorp [Member] | 2020 Wildfires, Economic and Noneconomic Damages [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 52,000 |  |  |
PacifiCorp [Member] | 2022 Wildfire [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of structures destroyed | Structure |  |  |  | 185 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of structures damaged | Structure |  |  |  | 11 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of injuries in wildfire | People |  |  |  | 12 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of fatalities in wildfire | People |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | Beachie Creek Fire [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of fires caused | Wildfire |  |  |  |  | 12 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of acres burned | a |  |  |  |  | 193,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | South Obenchain Fire [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of acres burned | a |  |  |  |  |  |  |  |  |  |  |  |  | 33,000 |  |  |  |  |  |
PacifiCorp [Member] | Echo Mountain Complex Fire [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of acres burned | a |  |  |  |  |  |  |  |  |  |  |  |  | 3,000 |  |  |  |  |  |
PacifiCorp [Member] | 242 Fire [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of acres burned | a |  |  |  |  |  |  |  |  |  |  |  |  | 14,000 |  |  |  |  |  |
PacifiCorp [Member] | Santiam Canyon Fires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of fires caused | Wildfire |  |  |  |  | 7 |  |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Court [Member] | 2020 Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of named plaintiffs | Plaintiff |  | 2,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of additional damages phase trials | Damage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9 |  |  |
Loss contingency estimates for additional damage expected |  |  |  |  |  |  |  |  |  |  | $ 497 |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Court [Member] | 2020 Wildfires [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of named plaintiffs | Plaintiff |  |  |  |  |  | 1,700 |  |  |  |  |  |  |  |  |  |  |  |  |
Multiplier used to determine economic and non-economic damages |  |  |  |  |  | 0.25 |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Court [Member] | Economic Damages [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  | $ 5 |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Court [Member] | Non-Economic Damages [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  | $ 25 |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit All Trials [Member] | 2020 Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, accrual interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9.00% |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Court First Trial [Member] | 2020 Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of named plaintiffs | Plaintiff |  |  |  |  |  |  |  |  |  |  | 17 |  |  |  |  |  |  |  |
Multiplier used to determine economic and non-economic damages |  |  |  |  |  |  |  |  |  |  | 0.25 |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Court First Trial [Member] | Economic Damages [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of damages awarded to plaintiffs |  |  |  |  |  |  |  |  |  |  | $ 92 |  |  |  |  |  |  |  |
PacifiCorp [Member] | James Case Multnomah County Circuit Additional Trials [Member] | 2020 Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of additional plaintiffs | Plaintiff |  |  |  |  |  |  | 1,500 |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | Minimum [Member] | 2020 Wildfires [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of acres burned | a |  |  |  |  |  |  |  |  |  |  |  |  | 500,000 |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  |  | $ 900 |  |  |  |  |  |  |  |  |  |  |  |
Number of structures destroyed | Structure |  |  |  |  |  |  |  |  |  |  |  |  | 2,000 |  |  |  |  |  |
PacifiCorp [Member] | Minimum [Member] | 2022 Wildfire [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of acres burned | a |  |  |  | 60,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
PacifiCorp [Member] | Minimum [Member] | James Case Multnomah County Circuit Court [Member] | Economic Damages [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  |  |  |  |  |  |  | $ 600 |  |  |  |  |  |  |
PacifiCorp [Member] | Minimum [Member] | James Case Multnomah County Circuit Court [Member] | Non-Economic Damages [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, sought amount |  |  |  |  |  |  |  |  |  |  |  | $ 1,000 |  |  |  |  |  |  |
Berkshire Hathaway Inc. (Parent) [Member] | BHE [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of outstanding common stock repurchased |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.12% |  |  |  |  |

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